GB808574A - Improved polyurethane plastics and method of making the same - Google Patents

Abstract

A process for producing light-fast polyurethanes comprises reacting a compound containing at least two reactive hydrogen atoms with a reaction product of a diisocyanate of the general formula <FORM:0808574/IV (a)/1> or <FORM:0808574/IV (a)/2> in which R represents one or more hydrogen atoms, alkyl radicals or halogen atoms with a polyfunctional alcohol, polyfunctional amine, hydroxy amine, hydroxy polyester, polyesteramide, polyalkylene ether or polyalkylene thioether, said reaction products containing at least two free NCO groups; or with a masked diisocyanate. As diisocyanates there are specified m-xylylene diisocyanate, 4- or 5-ethyl-m-xylylene diisocyanate, 5-isopropyl-m-xylylene diisocyanate, 4,5- and 4,6-dimethyl-m-xylylene diisocyanates, 2,4,5 - trimethyl - m - xylylene diisocyanate, 4-chloro-m-xylylene-diisocyanate, p - xylylene diisocyanate, 2,6 - dimethyl - p - xylylene diisocyanate, methyl - p - xylylene - diisocyanate and chloro-p-xylylene-diisocyanate. As polyfunctional compounds which may be reacted with such diisocyanates in amount to give products containing at least two -NCO groups there are specified trimethylol propane, glycerol, triethanolamine, diethylene glycol, diethanolamine, hexanetriol, methyl diethanolamine, linear polyesters, polyesteramides containing free hydroxyl and/or amino groups and polyalkylene ethers or thioethers with free hydroxyl groups. They may also contain polymerizable double bonds. Masked isocyanates for use in the process can be obtained by reacting the diisocyanates with phenols, diphenylamines, oximes, lactams, imides or compounds with reactive methylene groups such as diethylmalonate. Compounds containing a plurality of reactive hydrogen atoms to be reacted with the reaction products containing free or blocked -NCO groups include linear or branched hydroxyl polyesters, modified alkyd resins such as those from saturated or unsaturated fatty acids, hydrogenation products of ethylenecarbon monoxide copolymers, polyethers or polythioethers with free hydroxyl groups, partially saponified vinyl acetate polymerization products, epoxy resins, isocyanate modified polyesters and polyesteramides containing free hydroxyl groups and simple monomeric compounds such as water, di- or polyhydric alcohols, di- or polyamines, hydroxyamines and carboxylic acid amides. The reaction can be effected in solution, for example on a supporting surface, in a solvent such as esters, ethers or ketones which may be diluted with, for example, hydrocarbons or chlorinated hydrocarbons. Fillers such as sililic chalk, kaolin, titanium dioxide, dyestuffs, plasticisers and synthetic polymers such as cellulose derivatives may be used. The reaction may be accelerated by activators such as tertiary amines, phenates or heavy metal salts or retarded by, for example, acetic acid or acetyl chloride. The products can be used for producing films and foils, lacquering wires, as an adhesive for plates or bricks of glass or for application to paper, wood, metal or textiles. Foamed products are obtained generally using 0.5 to 1.5 mols. of di-isocyanate reaction product for each 17 g. OH groups in the polyhydroxy compound, with additional water, emulsifiers and accelerators. In examples: (1) a reaction product containing -NCO groups is prepared by reacting in ethyl acetate 1 mol. of trimethylol propane with 3 mols. of m-xylylene diisocyanate. This solution is applied to a support and exposed to moisture or steam to give an insoluble clear film; (2) an ethyl acetate solution of an adipic acid/phthalic acid/trimethylol propane hydroxy-polyester and an isocyanate-containing reaction product from 3 mols. of 4,6-dimethyl-1,3-xylylene diisocyanate and 1 mol. of trimethylol propane is applied to a support and gives a hard coating on standing; (3) a similar product to (2), using, however, a p-xylylene diisocyanate/trimethylol propane reaction product is prepared; (4) a solution in ethyl acetate of a hydrogenation product of an ethylene/carbon monoxide polymer is mixed with an isocyanate group-containing product from p-xylylene diisocyanate and trimethylol propane; (5) an isocyanate-modified polyester is prepared from (a) an adipic acid/ethylene glycol hydroxy-polyester; (b) an adipic acid diethylene glycol hydroxy polyester; and (c) m-xylylene diisocyanate. The product is milled with a mixture of china clay, titanium dioxide, paraffin wax, a tertiary amine prepared by reacting phenyl isocyanate and N-methyl-diethanolamine, and a solution of the trimethylol propane m-xylylene diisocyanate reaction product of Example (1). The mixture is used to prepare laminated cotton fabric on a calender at 40 DEG to 80 DEG C.; (6) to an ethyl acetate solution of the isocyanate-modified polyester of Example (5) and the trimethylol propane-m-xylylene diisocyanate reaction product of Example (1) is added a reaction product of phenyl isocyanate and N-methyl-diethanolamine. The solution is sprayed on to glass, heated, and the reaction product is removed as a foil. The solution can also be applied to a fabric which is formed into a laminate.